Lamp focusing device for electric fixtures



Aug. 31, 1937. w, KNAPP 2,091,782

LAMP FOCUSING DEVICE FOR ELECTRIC FIXTURES Filed Feb. 1, 1937 INVENTOR.

W/Y/AQM lfx7 BY ATTO NEY.

Patented Aug. 31, 1937 UNITED STATES PATENT OFFICE LAMP FOCUSING DEVICEFOR ELECTRIC FIXTURES 1 Claim.

This invention relates to electric lamp focusing or controlling devices,and has for one of its objects the provision of a light diffusing bowlor shade-holder which may be readily raised or lowered upon its stem orsupport relatively to the lamp so as to permit its use in connectionwith a variety of sizes of lamps.

Another object of the invention is to provide such a holder which isopen at the top so as to permit the heat generated by the lamp to bedissipated and thus eliminate a fire hazard by preventing the wiringfrom becoming overheated as is the case with the closed shade holdersnow commonly used.

A further object of the invention is the provision of a device of thecharacter described which may be operated without the use of tools, andone in which the use of socket extensions is avoided.

Another object is to produce a device of the character described inwhich the maximum simplicity of construction and operation is secured. 7Other objects and advantages will appear as the nature of theimprovements is better understood, the invention consistingsubstantially in the novel arrangement and co-relation of parts hereinfully described and illustrated in the accompanying drawing, whereinsimilar reference characters are used to describe corresponding partsthroughout the several views, and then finally pointed out andspecifically defined and indicated in the appended claim.

The disclosure made the basis of exemplifying the present inventiveconcept suggests a practical embodiment thereof, but the invention isnot be restricted to the exact details of this disclosure, and thelatter, therefore, is to be understood from an illustrative, rather thana restrictive standpoint.

The inventive idea involved is capable of re- 40 ceiving a variety ofmechanical expressions, one

of which, for the purpose of illustration, is shown in the accompanyingdrawing, in which- Figure 1 is a view in side elevation of an electriclighting fixture showing my improved holder as 45 applied thereto;

Figure 2 is a sectional view at an enlarged scale of my improved holderand the clamping means therefor;

Figure 3 is a top plan view thereof looking from 50 the top of Fig. 2;

55 and Fig. 7 is a top plan view thereof.

Referring now to the drawing in detail I0 indicates an electric lightingfixture, comprising a tube or stem I I through which passes the electricwiring I2 which is suitably connected to the electric socket I3 which inturn is secured to the lower end of the stem I I by means of a set screwI4.

Mounted on the stem or pipe I I is a bushing I5 provided at its lowerend with an enlarged portion or boss I Ii having a plurality of threadedholes or openings II. The upper portion of the bushing I5 comprises areduced cylindrical screw threaded portion I8 tapered and unthreaded atits free end I9 and has cross slots which extend approximately to thetop of the enlarged portion I6. A nut 2|, having a threaded opening 22terminating in an unthreaded tapered portion 23, provides means forclamping the bushing I5 to the stem II in desired position.

A cylindrical shell or holder 24 open at both ends and made of anysuitable material such as for instance metal, glass, etc. is secured tothe bushing I5 by means of screws 25 which pass through the said shelland are threaded into the threaded openings I! in the boss I6. Theholder 24 is provided near the bottom thereof with a plurality ofanchoring openings 26 in which chains or other suspension means 21 maybe anchored for supporting a reflector or light difiusing bowl 28. g

In Fig. 2 of the drawing I have shown an electric bulb 30 provided witha substantially long neck 3I used in connection with my device. In orderthat I may employ a small lamp with a much shorter neck the nut 2| isslightly loosened and. the holder may be moved up to the dot and dashposition shown in said Fig. 2 or to any other desirable position, thenut may then be tightened again and a smaller lamp inserted into thesocket I3. It will also be seen that due to the opening 32 at the top ofthe holder 24 any heat generated by the lamp 30 will be dissipatedtherethrough and the wiring I2 will be prevented from becomingoverheated, thus eliminating the possibility of short circuiting orbreak-down of the wire insulation.

From the foregoing it will be seen that I have provided a simple andefiicient means for adjustably securing a globe or light diffusing bowlholder to a support or stem, so that the said globe or holder may bemoved up or down with respect to the electric light bulb for properlyfocusing the light, and to dissipate any excess heat generated by thelamp.

Having described my invention, What I claim as new and desire to secureby Letters Patent is:

A holder for securing a light difiusing device to a fixture stem,comprising a holder shell open at the top and bottom and provided withradially spaced apart openings near the top thereof, a bushing having acentral bore for the reception of the stem, a boss on the bushing havingradially spaced apart threaded openings, screws passing through thethreaded openings in the holder shell and boss, and exteriorly threadedlongitudinally split shank on the bushing above the boss, a taperedunthreaded end on the shank, and a nut having a threaded openingterminating in a tapered unthreaded portion for releasably clamping thebushing to the stem.

WILLIAM KNAPP.

